<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            background-color: black;
        }
        .adiv{
            width: 630px;
            height: 395px;
            border: 1px solid white;
            margin:150px auto;
            text-align: center;
        }
        .ali{
            list-style-type: none;
            float: left;
            margin: 5px;
        }
    </style>
</head>
<body>
    <div class="adiv">
        <ul class="aul">
            <li class="ali">
                <img src="homework/images/01.jpg" alt="">
            </li>
            <li class="ali">
                <img src="homework/images/02.jpg" alt="">
            </li>
            <li class="ali">
                <img src="homework/images/03.jpg" alt="">
            </li>
            <li class="ali">
                <img src="homework/images/04.jpg" alt="">
            </li>
            <li class="ali">
                <img src="homework/images/05.jpg" alt="">
            </li>
            <li class="ali">
                <img src="homework/images/06.jpg" alt="">
            </li>
        </ul>
    </div>
</body>
<script src="jquery-3.6.0.js"></script>
<script>
    $(".aul>li").mouseenter(
        function(){
            $(this).find('img').css({opacity:'1'})
            $(this).siblings('li').find('img').css({opacity:'0.4'});
        }
    )
    $(".aul>li").mouseleave(
        function(){
            $(".aul>li>img").css({opacity:'1'});
        }
    )
</script>
</html>